1. Field of the Invention
The present invention relates to a saddle type deflection coil of a deflection yoke mounted on a television receivers and display devices, etc.
2. Description of the Prior Art
With recent development of television receivers to application to those of hi-vision and with recent appearance of highly fine display devices, specifications of color mismatching on a screen of a cathode-ray tube of those devices, i.e., convergence of the same gets increasingly severe, and accompanied therewith further accurate control of a deflection magnetic field becomes earnestly desired.
One type of deflection yokes for use in television receivers and display devices, etc., includes as conventionally known a horizontal deflection coil mounted inside a resin-made bobbin and a vertical deflection coil mounted outside the same. A horizontal deflection coil of a deflection yoke of this type using a bobbin is of a saddle type and a vertical deflection coil is of a saddle type or of a toroidal type.
Referring to FIG. 1, there is illustrated a saddle type deflection coil for use in general deflection yokes in an exemplified manner. In the illustrated saddle type deflection coil 1, a bonding agent is applied on the outer periphery of a winding 11 composed of a conductor wire (including a Litz wire) covered with an insulating layer 4, and the winding 11 is wound in a coil winding groove 5 with the aid of a metal mold 2 having a flange 3, as illustrated in FIG. 2. The winding 11 is constructed by winding separate independent single wires, not bundled in every group of wire thereof using an automated machine. In succession, the coil so wound is supplied with electric power to heat and melt the bonding agent applied on the outside of the insulating agent applied on the outside of the insulating layer 4 for bonding of the wiring in itself, and then, the coil is separated from the metal mold 2 for formation of such a deflection coil as illustrated in FIG. 1. The resulting saddle type deflection coil 1 is complicated in its configuration for accurate control of an associated magnetic field distribution. The metal mold 2 serving to form the deflection coil therefore includes a plurality of winding grooves 5 formed successively therein. An intersecting region where the winding 11 traverses from one groove 5 to the other separate groove is shaped into a wider one region to permit the winding 11 to traverse to the next groove 5 with ease.
The prior art winding method described above however, suffers from the following difficulties: Owing to a change in the direction of tension when the wiring 11 being wound is displaced as illustrated in FIG. 2, and the order of the winding of the winding 11 is changed such winding as designated by a design becomes impossible. Further, a displaced state of each of windings 11 of the mass-produced deflection coils 1 causes variations thereof for each article, which makes it impossible to accurately control a deflection magnetic field. Further, variations in mass-produced articles cause lowering of the yield, and hence the prior art winding method is disadvantageous. Even in the afore-described prior art system, the wiring 11 is reduced and biassed winding as the width of the coil winding groove is narrowed to satisfy an original design, which causes another problem of coil performance because of a ratio L/R between inductance L and resistance R is reduced. To solve the problems with the aforementioned prior art, the present inventors have proposed a method wherein, instead of the prior art winding 11 comprising independent and separate single wires, there are employed and wound multicore parallel conductor wires 15 as illustrated in FIGS. 3 through 5. Such a multicore parallel conductor wire 15 is formed into various forms using a conductor wire 8 (including a Litz wire and a square wire) which is covered with an insulating layer 4. The width of parallel conductor wire 15 is set to be substantially comparable with the width of the coil winding groove 5 of the metal mold 2. In FIG. 3, a multicore parallel conductor wire 15 is constructed by parallel arranging of a plurality of conductor wires 8 and applying a bonding agent 6 to the lower halves of those wires 8 for bonding. In FIG. 4, a multicore parallel conductor wire 15 is constructed by applying a bonding agent 6 on one surface of a resin sheet 7 and bonding parallely-arranged conductor wires 8 to the one surface of the resin sheet 7. Further, in FIG. 5, a multicore parallel conductor wire. 15 is constructed by uniformly applying a bonding agent 6 over the entire surface of the external circumference of conductor wires 8 is parallel and arranging the conductor wires 8 for bonding between adjacent conductor wires 8.
In the just-mentioned prior art example proposed by the present inventors, upon formation of a saddle type deflection coil 1 of a complicated configuration, the prior art metal mold 2 of FIG. 2 is employed and the foregoing multicore parallel conductor wire 15 is wound in a continuous groove 5 in the metal mold 2 to form the deflection coil. Thereupon, such a deflection coil encounters a problem that the multicore parallel conductor wire 15 is twisted in a winding area of an intersection part 9 where the wire traverses from one groove to another separate groove as has been mentioned above. The prior art winding 11 does not suffer from such a problem because a single wire is freely movable in the intersection part 9, while the multicore parallel conductor wire 15 is inevitably twisted because it is restricted in the form of a band.
Additionally, the intersection part is configured to be wider, so that the multicore parallel conductor 15 is freed widthwise in the wider groove and is displaced in the same direction. Such twist and displacement make it difficult to accurately control a deflection magnetic field, and hence even the use of the multicore parallel conductor wire does not improve the performance of the deflection coil.